chinese visa requirement for US citizen with short layover leaving shanghai airport to stay hotel

arriving Feb 27,2016 3 passengers arriving from San Francisco leaving Pudong airport staying at Ramada overnight flying out next day to Okinawa; then returning March 13, 2016 staying Ramada between flights from Okinawa layover Shanghai flight out San Francisco next day. Does the 72 hr entry without chinese entry permit applicable I am getting varying information. I do not want a surprise when I get there. Thankyou